/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.hasor.boot.launcher.archive;
import net.hasor.boot.launcher.jar.JarFile;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;
import java.util.jar.JarEntry;
import java.util.jar.Manifest;
/**
 * {@link Archive} implementation backed by a {@link JarFile}.
 *
 * @author Phillip Webb
 * @author Andy Wilkinson
 */
public class JarFileArchive implements Archive {
    private static final String  UNPACK_MARKER = "UNPACK:";
    private static final int     BUFFER_SIZE   = 32 * 1024;
    private final        JarFile jarFile;
    private              URL     url;
    private              File    tempUnpackFolder;
    public JarFileArchive(File file) throws IOException {
        this(file, null);
    }
    public JarFileArchive(File file, URL url) throws IOException {
        this(new JarFile(file));
        this.url = url;
    }
    public JarFileArchive(JarFile jarFile) {
        this.jarFile = jarFile;
    }
    @Override
    public URL getUrl() throws MalformedURLException {
        if (this.url != null) {
            return this.url;
        }
        return this.jarFile.getUrl();
    }
    @Override
    public Manifest getManifest() throws IOException {
        return this.jarFile.getManifest();
    }
    @Override
    public List<Archive> getNestedArchives(EntryFilter filter) throws IOException {
        List<Archive> nestedArchives = new ArrayList<Archive>();
        for (Entry entry : this) {
            if (filter.matches(entry)) {
                nestedArchives.add(getNestedArchive(entry));
            }
        }
        return Collections.unmodifiableList(nestedArchives);
    }
    @Override
    public Iterator<Entry> iterator() {
        return new EntryIterator(this.jarFile.entries());
    }
    protected Archive getNestedArchive(Entry entry) throws IOException {
        JarEntry jarEntry = ((JarFileEntry) entry).getJarEntry();
        if (jarEntry.getComment().startsWith(UNPACK_MARKER)) {
            return getUnpackedNestedArchive(jarEntry);
        }
        try {
            JarFile jarFile = this.jarFile.getNestedJarFile(jarEntry);
            return new JarFileArchive(jarFile);
        } catch (Exception ex) {
            throw new IllegalStateException("Failed to get nested archive for entry " + entry.getName(), ex);
        }
    }
    private Archive getUnpackedNestedArchive(JarEntry jarEntry) throws IOException {
        String name = jarEntry.getName();
        if (name.lastIndexOf('/') != -1) {
            name = name.substring(name.lastIndexOf('/') + 1);
        }
        File file = new File(getTempUnpackFolder(), name);
        if (!file.exists() || file.length() != jarEntry.getSize()) {
            unpack(jarEntry, file);
        }
        return new JarFileArchive(file, file.toURI().toURL());
    }
    private File getTempUnpackFolder() {
        if (this.tempUnpackFolder == null) {
            File tempFolder = new File(System.getProperty("java.io.tmpdir"));
            this.tempUnpackFolder = createUnpackFolder(tempFolder);
        }
        return this.tempUnpackFolder;
    }
    private File createUnpackFolder(File parent) {
        int attempts = 0;
        while (attempts++ < 1000) {
            String fileName = new File(this.jarFile.getName()).getName();
            File unpackFolder = new File(parent, fileName + "-spring-boot-libs-" + UUID.randomUUID());
            if (unpackFolder.mkdirs()) {
                return unpackFolder;
            }
        }
        throw new IllegalStateException("Failed to create unpack folder in directory '" + parent + "'");
    }
    private void unpack(JarEntry entry, File file) throws IOException {
        InputStream inputStream = this.jarFile.getInputStream(entry);
        OutputStream outputStream = new FileOutputStream(file);
        byte[] buffer = new byte[BUFFER_SIZE];
        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
        outputStream.flush();
    }
    @Override
    public String toString() {
        try {
            return getUrl().toString();
        } catch (Exception ex) {
            return "jar archive";
        }
    }
    /**
     * {@link Archive.Entry} iterator implementation backed by {@link JarEntry}.
     */
    private static class EntryIterator implements Iterator<Entry> {
        private final Enumeration<JarEntry> enumeration;
        EntryIterator(Enumeration<JarEntry> enumeration) {
            this.enumeration = enumeration;
        }
        @Override
        public boolean hasNext() {
            return this.enumeration.hasMoreElements();
        }
        @Override
        public Entry next() {
            return new JarFileEntry(this.enumeration.nextElement());
        }
        @Override
        public void remove() {
            throw new UnsupportedOperationException("remove");
        }
    }
    /**
     * {@link Archive.Entry} implementation backed by a {@link JarEntry}.
     */
    private static class JarFileEntry implements Entry {
        private final JarEntry jarEntry;
        JarFileEntry(JarEntry jarEntry) {
            this.jarEntry = jarEntry;
        }
        public JarEntry getJarEntry() {
            return this.jarEntry;
        }
        @Override
        public boolean isDirectory() {
            return this.jarEntry.isDirectory();
        }
        @Override
        public String getName() {
            return this.jarEntry.getName();
        }
    }
}
